The invention relates to a measuring transducer with a sensor for converting a measured quantity detected therewith into an electrical sensor signal. More particularly, the invention relates to such a measuring transducer with a signal processing unit adapted to preprocess the sensor signal into a measuring signal and to generate an error message signal, and with a data interface for transmitting the measuring signal and the error message signal.
A pressure transducer, for example, has a pressure sensor whose sensor signal is amplified, digitized, analyzed and corrected for linearity and temperature response in a transducer-internal signal processing unit. The measuring signal thus preprocessed is fed via a data interface, e.g. PROFIBUS or HART, to the communication system of a technical installation in which the transducer is installed. Any hardware or software errors occurring in the measuring transducer are indicated on the measuring transducer. In addition, the error is provided as digital diagnostic information at the data interface. In a 4 . . . 20 mA interface, the error can also be transmitted in analog form as a current value outside this predefined signal level range in accordance with NAMUR Recommendation NE43, e.g., as a downscale value of <3.6 mA or an upscale value of >21 mA.